Determination of cleanliness in industrial, health care and other settings is important for maintaining good hygiene and sanitation. For example, the surfaces of equipment used for food handling, storage or processing are major sources of microbial and allergen contamination. Microbial contamination can lead to decreased shelf life of products and, if pathogens are present, transmission of disease. Similarly, unexpected allergens on food contact surfaces may contaminate food. Such contamination has the potential to cause adverse reactions, such as an allergic reaction including hives, anaphylaxis and death, in sensitive people who consume or otherwise contact the contaminated food.
Microbial culturing can be used to determine the presence of microorganisms. Culturing, however, is time consuming and, therefore, the necessary “real time” feedback to sanitation and food preparation personnel may not be available. As a result, food exposed to surfaces that are later found to contain potentially harmful microorganisms could enter the food supply.
During the 1990's various rapid and efficient test methods and devices were developed for the detection of contamination on surfaces. Some of these methods do not detect microbes directly but instead use markers such as adenosine triphosphate (ATP) that are indicative of the presence of microbes or residual food contamination of a surface. One such apparatus is the POCKETSWAB-PLUS (POCKETSWAB is a registered trademark of Charm Sciences, Inc. of Lawrence, Mass.), which rapidly and efficiently detects ATP on surfaces. The POCKETSWAB apparatus detects ATP through the reaction of luciferin and luciferase in the presence of ATP to generate luminescence (light). Luminescence can be measured using a luminometer. Such ATP detection systems generally provide the user with an average reading of relative light units (RLU's) over a time period, for example 5 seconds.
Also during the late 1990's, allergen tests were developed to detect allergenic components of foods. These tests are typically in the ELISA (enzyme linked immunosorbent assay) format and require 30 minutes or more to obtain a result. ELISA allergen tests have generally been more sensitive for detecting allergenic food residues than previously available ATP tests such as the POCKETSWAB.
Maximizing the sensitivity of ATP detection assays and systems, particularly single service ATP detection assays, could expand their usefulness. For example, a sensitive ATP detection system could be used to rapidly screen a surface for food residue at the level of allergen test detection. Regulations require sensitivity of 5 parts per million peanut residue for tests that detect peanut allergens.